BCL2 and acute myeloid leukemia: Consequently, they have revealed that elevating Bcl-XL and Bcl-2 levels mediate the anti-apoptotic impact of MS-5 stromal cells on primary AML cells and HL-60 cells, and the elevated expression level of Bcl-2 in stromal-supported AML blasts in vitro is associated with chemotherapy resistance in vivo [74].